Thermionic valve



1934- G. MAIRCONI El AL 'rm-murom'c VALVE Filed 00*.."14. 192s INVENTOR GUGLIELMO MARCONI BY CHAR S S.FRANKLIN TORNEY Patented Nov. 2o, 1934 PATENT .o' FIcE 1,981,058 THERMIONIQ vALv'E Guglielmo Marconi, Strand, London, and Charles Samuel Franklin, Buckhurst Hill, England, assignors to Radio Corporation of America, a corporation of Delaware Application October 14, 1926, Serial-No. 14l,599 In- Great Britain October 14, 1925 13 Claims. (Cl. 250-275) This invention relates to thermionic valves, and more especially to valves suitable for the production of very short waves of the order of two or three metres long or even less.

In hitherto known arrangements for generating waves by means of thermionic valves, the extent to which the wave length can be reduced is limited by the physical dimensions of leadingin wires and seals necessary, and by the length of such leads.

According to the present invention the whole primary circuit associated with the valve is located within the valve itself, and preferably the arrangement is such that all or some of the inductances and capacities comprising the said primary circuit are formed by the electrodes themselves and the supports therefor.

In one form of construction, the grid and anode of a three electrode valve are arranged concentrically about the filament which is supported from the glass stem of the valve by the usual filament seals. The gridis supported by means of metal strips lying along the surface of an imaginary cylinder, attached to a metal ring surrounding the stem. The anode is supported by means of metal strips ly g along the surface of an imaginary cylinder, attached to a second metal ring surrounding and supported by the first metal ring, but insulated therefrom by mica or the like. Connection is made-to the grid and anode by means of two small leads sealed in the envelope that for the anode carrying the high tension supply, and that for the grid carrying the grid current.

It will be seen that with this arrangement the oscillatory circuit is comprised by the condensers formed by the grid and anode and by the rings supporting them in series with inductances formed by the metal strips supporting the grid;

and anode respectively. Thus the primary circuit is wholly inside the valve and therefore the seals do not have to carry any heavy high frequency currents;

In amodification, which is, in eflect, two valves in a single envelope, two filaments are provided at opposite ends of a glass bulb. Each filament has associated therewith a grid and an anode supported in any convenient way, the two grids being connected together and also the two anodes, by means of metal strips lying along the surfaces of imaginary cylinders.

Connection is made to the anode and grids by means of two small leads.

This construction has been found to give a very short wave length for a given length of valve, the said wave length being generally about twice the distance between the two anodes, if concentric cylinders be employed for connecting the anodes and grids.

The invention is illustrated in the accompanying drawing, in which Figure 1 is a. schematic arrangement of a single valve, according to the invention, and Figure 2 is a schematic arrangement of a double valve according to the invention.

Referring to Figure 1, the valve comprises an evacuated bulb B, containing a filament F, a grid G, and an anode A, supported upon a glass stem W. Around this stem are mounted two metal rings, 0 and P, with an insulating ring M between them. Connection is made to these two rings by wires which pass thru seals GS and AS respectively. The grid is supported from the ring 0 by means of a number of metal strips X, and the anode is supported from the ring P by means of a number of metal strips Y. The capacity between the rings 0 and P should be large compared with the capacity between the anode A and grid G.

It will be seen that the anode-grid capacity, in series with the capacity between the rings 0 and P, and the inductances of the strip connections X and Y, constitute an oscillatory circuit which may easily be constructed to have an extremely high natural frequency. The seals AS and GS, through which connections are made to the, anode and grid respectively, carry merely the anode feed current and grid currents respectively, and do not have to carry the high frequency current. They can therefore be made comparatively small.

The modification shown in Figure 2 is a double valve having two sets of filaments, grids, and anodes, F1, G1 and A1 and F2, G2 and A2, mounted in a single bulb B.

The anodes A1 andAz are connected together by metal strips Y, the grids G1 and G1; being similarly connected by metal strips X. From. the centre points of these strips, connections are brought to the outside of the valve through seals AS and GS respectively.

The anodes and grids may be supported in any convenient manner from the stem of the valve,

capacity between the anode A1 and the grid G1,

cluded in the envelope of the valve, but generan envelope enclosing a complete oscillatory circuit, said circuit consisting of a grid electrode, an anode electrode in spaced relation with respect thereto, a capacitive element between said grid and anode, and an inductance element, all of said elements being supported from one end only of said envelope, the value of the capacity of said capacitive element being large compared with the capacity between the anod and grid due tov the space between them.

2. An oscillation generator, comprising an envelope which includes a reentrant stem, a filament supported by leadssealed in said stem, a cylindrical ring of conducting material supported in said envelope, a second cylindrical ring of conducting material concentric to said first named ring but insulated therefrom in said envelope, a control electrode supported by said first named ring, and an anode supported by said last named ring, said elements and supports forming a complete oscillation circuit within said tube.

3. A discharge tube for producing high frequency oscillations, comprising a cathode, a grid surrounding the cathode, an anode surrounding the grid, and two metal rings insulated from each other to form a condenser, the grid being sup-.

ported from one of the metal rings by means of metal strips, the anode-being supported from the other metal ring by means of metal strips, the whole being enclosed within a single evacuated envelope.

4. A discharge tube for producing high frequency oscillations, comprising a cathode, a grid arranged around the cathode, an anode surrounding the grid, two metal rings insulated from each other to form a condenser, the grid being supported from one of the metal rings by means 'of metal strips, the anode being supported from the other metal ring by means of metal strips, and an antennaiparallel to said anode and coupled thereto, the whole being enclosed within a single evacuated envelope. 7

5. An oscillation generator comprising two space current units within a single envelope and conductors, also within the envelope, connecting corresponding electrodes of the two space current units and forming a complete oscillatory circuit therewith. I

6. An evacuated envelope'containing two triode structures spaced apart and also containing conductors having substantially rectilinear parts, connecting together corresponding elements of the triode structures and forming therewith a complete oscillatory circuit. 75A]; oscillatory system comprising two sets of space current device electrodes within an envelope, a plurality of conductors with their 'centre lines disposed on a circle, and connecting one a pair of corresponding electrodes, and a plurality of'conductors with theirmid-points disposed on I a circle concentric with the aforementioned cir-' cle and connecting another pair of correspond- ;ing electrodes.

8, A high frequency oscillator comprising a vessel containing a radio oscillating circuit, and a substantially straight linear radiating element mounted within said vessel.

9. An electron discharge device comprising an evacuated container enclosing an electron emitting cathode an anode and a grid, and means completing a high frequency oscillatory circuit. I

and a high frequency antenna within said envelope parallel to said electrodes.

10. A thermionic oscillation generator comprising an envelope enclosing a complete oscillatory circuit, said circuit consisting of a grid electrode, an anode electrode in spaced. relation with respect thereto, a capacitive element between said grid and anode, and an inductance elem'ent,.,a1l of said elements being supported from one end only of said envelope, the value of the capacity of said capacitive element being large compared with the capacity between the anode and grid due to the space between them, and a straight linear aerial in the form of a wire also located within said envelope and spaced from said electrodes and electrostatically coupled thereto.

space current units within a single envelope, each of said units comprising a cathode, anode and control electrode, and conductors also within the envelope connecting corresponding grid and anode electrodes of thetwo space current units together to form a complete oscillatory circuit therewith, the individual cathodes of said re- 11. An oscillation generator comprising two spective unitsbeing supported at opposite ends of said envelope.

12. An oscillation generator comprising two space current units within a single envelope, each of said units comprising a cathode, anode and control electrode, and conductors also within the envelope connecting corresponding grid and anode electrodes of the two space current 'units together to form a"complete oscillatory circuit therewith, the individual cathodes of said respective units 'being supported at opposite ends of said envelope, and a straight linear aerial in the form of a. wire electrostatically coupled to said anodes. I v 13. A thermionic valve, comprising'an envelope which includes a reentrant stem, a filament CHARLES SAMUEL ram. 

